<!DOCTYPE html>
<html>
<head>
<meta charset = "utf-8" />
 <title>弹幕案例</title>
<!-- <script src = "http://libs.baidu.com/jquery/1.10.2/jquery.min.js"></script>-->
 <script src="js/jquery-2.1.0.js"></script>
 <script>
 $(function(){
  var boxDom = $("#boxDom");
  //var domContent = $("#domContent");
 
  var top, right;
 
  var pageWidth = parseInt($(document).width());
  var pageHeight =parseInt($(document).height());
 
  //点击按钮
  $("#btn").bind("click",auto);//按钮绑定方法
  //按下回车
  document.onkeydown = function(){
   if(event.keyCode == 13){
    auto();
   }
  }
  function auto(){
  //1.获取输入的字符串
  var str = $(".text").val();
  //2.生成一个元素
  var createSpan = $("<span class = 'string' ></span>");
 
  //3.给生成的元素赋值
 
  createSpan.text(str);
 
  //为了页面友好，清空刚刚输入的值
  $(".text").val("");
 
 //生成元素一个随机的位置，为了使每条弹幕都出现在屏幕上不同的位置
  top = Math.floor(Math.random()*pageHeight);
 
 
 createSpan.css({"top":top, "right": -400, "color": getRandomColor()});
  boxDom.append(createSpan);
 
  //4.设置元素的动画效果，animate(css样式值，时间， 执行完动画调用的方法)
 
  //页面上有N个span，只让最后一个动起来
  var spandom = $("#boxDom>span:last-child");//找到最后一个span
  spandom.animate({"right":pageWidth+300},10000,function(){
   //移除元素
   $(this).remove();
 
  });
  }
  //定义一个可以生成随机颜色的方法,可以使每条弹幕的颜色不同
  function getRandomColor(){
   var colorArr = ['1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'];
   var color = "";
   for(var i = 0; i < 6; i++){
    color += colorArr[Math.floor(Math.random()*16)]; 
   }
   return "#"+color;
  }
 
 });
 </script>
 <style type="text/css">
 html,body{
  margin: 0px;
  padding: 0px;
  width: 100%;
  height: 100%;
  font-family: "微软雅黑";
  background: #ccc;
 }
 .boxDom{
  width: 100%;
  height: 100%;
  position: relative;
  overflow: hidden;
 }
 .idDom{
  width: 100%;
  height: 60px;
  background:#666;
  position: fixed;
  bottom: 0px;
 }
 .contet{
  width: 500px;
  height: 40px;
  position: absolute;
  top: 0px;
  right: 0px;
  bottom: 0px;
  left: 0px;
  margin: auto;
 
 }
 .title{
  display: inline;
  font-size: 24px;
  vertical-align: bottom;
  color: #ffffff;
  padding-left: 300px;
 }
 
 .text{
  width: 300px;
  height: 30px;
  border:none;
  border-radius:5px;
  font-size: 20px;
  margin-left:60px;
 }
 .btn{
  width: 60px;
  height: 30px;
  color: #ffffff;
  background-color: red;
  border:none;
  font-size:16px;
  margin-left:60px;
  margin-top: 20px;
 }
 .string {
   width: 300px;
   height: 40px;
   margin-top: 20px;
   position: absolute;
   color: #000;
   font-size: 20px;
   font-family: "微软雅黑";
 
 }
 </style>
</head>
<body>
<div class = "boxDom" id = "boxDom">
 <img src="img/001.jpg" style="width:100%; height:100%" />
 <div id = "idDom" class = "idDom">
  <div class = "content">
   <p class = "title"> 说点什么:</p>
   <input type = "text" class = "text"/>
   <button type = "button" class = "btn" id = "btn" >发送</button>
  </div>
 </div>
</div>
</body>